ImageReader: fix documentation, relax some guarantees
ImageReader: fix documentation, relax some guarantees

MediaCodec does not guarantee any of this.

Change-Id: Id73c917baad9ca72de87b98c16374505c8028e86

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base